Electric arc furnace (EAF) dust is produced in the steel making process. This dust contains hazardous materials and the dust is collected in a bag house for further processing. The primary hazardous materials in EAF dust are lead, cadmium and hexavalent chromium. Because these constituents leach, most EAF dust from the production of carbon steel is considered hazardous. One solution to this problem has been to process the EAF dust so that it is stabilized and will not leach. The stabilized EAF dust is then placed in a landfill. The cost of transporting this material and landfill cost can be large. A second solution has been to use a pyromettalurgical process that uses a Waelz kiln to heat the dust and fume zinc and other impurities off. Before the EAF dust can be processed it has to be mixed with coke (carbon) and sand. The carbon acts as a reductant and as all or part of the fuel. The sand controls the chemical and physical properties of the slag in the kiln. The mixture has to be heated to very large temperatures 1200–1300 degrees centigrade and the left over slag or residue has the consistency of hot fudge which makes it difficult to work with in various material handling steps. While this process is able to remove most or all the hazardous materials which have commercial value, the energy costs are very large and the process requires a very large capital outlay. The large capital outlay is necessary because the process is only economically viable if it processes a large amount of the EAF dust. As a result, the EAF dust has to be transported to a central location for processing. This increases the cost of the process.
Thus there exists a need for a process that can economically remove the hazardous material and recover the commercially valuable material from EAF dust.